Digital holography-secured scheme using only binary phase or amplitude as ciphertext

A digital holography-secured scheme is presented by using binary phase or amplitude. The input image is encrypted based on double random phase encoding, and a complex-valued wavefront in the charge-coupled device plane is extracted by using digital holography. Subsequently, only the phase component of the extracted complex-valued wavefront is maintained, and is further binarized. Different from conventional methods, an interesting finding in this paper is that in addition to binary phase, binary amplitude originating from the binarized phase pattern can also be applied as ciphertext. During optical decoding, the decrypted image cannot visually render clear information about the input, and the authentication is further conducted. The binary phase or amplitude pattern can be flexibly applied as ciphertext, and the fully optical approach can be implemented for the decoding. The ciphertext is effectively compressed, which can facilitate the storage and transmission in practical applications.